1. Field of the Invention
The disclosed invention relates to a photoelectric conversion device using a photovoltaic effect of a semiconductor. The disclosed invention includes a photoelectric conversion device in which a support substrate is provided with a semiconductor layer.
2. Description of the Related Art
To deal with global environmental issues in recent years, the market for photoelectric conversion devices typified by residential photovoltaic systems and the like has expanded. Bulk photoelectric conversion devices including single crystal silicon or polycrystalline silicon, which have high conversion efficiency, have already been put into practical use.
The photoelectric conversion devices including single crystal or polycrystalline silicon are manufactured by being cut out of large silicon ingots. However, since it takes a long time to manufacture large silicon ingots, the productivity is low. Accordingly, the supply of silicon ingots is insufficient and cannot respond to the expansion of the market.
As the shortage of raw materials of solar cells becomes obvious, thin-film photoelectric conversion devices including an amorphous silicon thin film or a microcrystalline silicon thin film have attracted attention. In the thin-film photoelectric conversion devices, silicon thin films are formed over support substrates by a variety of chemical or physical growth methods. Therefore, it is said that the thin-film photoelectric conversion devices enable resource saving and cost reduction as compared with the bulk photoelectric conversion devices.
As an example of a thin-film photoelectric conversion element, an element that is provided with a protuberance which sticks out of an interface side of an electrode into a light absorption layer has been proposed (see Patent Document 1). The protuberance which sticks out into the light absorption layer is provided to serve as a path of photogenerated carriers, which improves the collection efficiency and prevents light degradation.